Tunneling deeper

Interview by Katherine Duke '05

Jonathan Friedman, a former newspaper reporter, earned degrees from Vassar College and The City University of New York and did monumental research at both CUNY and Stony Brook University before joining the physics department at Amherst in 2001. In August 2008, the journal Nature ranked one of his early discoveries among the greatest milestones in more than a century of spin physics.

On the police beat

People think that the greatest successes in my career have been the big scientific discoveries, but actually some of my favorite accomplishments occurred when I was a reporter for a weekly paper in central New Jersey. There was a police chief in this town who many considered crazy—dictatorial in style. Part of my job was to cover the police beat, but every week the chief would say, “Oh, everything’s been quiet.” The mayor and executive committee wanted to promote this idea that they had this sleepy town. I would write in the police log, “Police had no crime to report for the nth week in a row.” I thought that after so many weeks they’d start breaking down and telling me stuff. That didn’t happen, so I looked at the court docket, and then I went to the library and figured out what all the codes meant and what all the crimes were. Then I set up a meeting with the chief. I said, “You know, chief, according to the court docket, Patrolman Walsh arrested somebody on Aug. 27…” and I went through the list. And he said, “Well, the days you called, there wasn’t anything happening that day.” This turned into a big story, and eventually we got the county prosecutor involved.

On what happened next

A couple months later, I got a call from one of my sources, who said, “Something’s happening with the chief, but I can’t tell you what it is.” So I called up another source, ostensibly to talk about something else. I said, “Oh, so you know what’s going on with the chief.” I just pretended I knew everything, hoping he would reveal the details. Eventually it came out that the chief’s son had been on the payroll as a dispatcher for the department. He had only worked there a few weeks. He continued to draw a weekly paycheck after he left, however, even after he stopped being a dispatcher. A few days later, I got a call from the mayor that the chief was retiring “for health reasons.”

On that big discovery

In 1996, while I was a graduate student at CUNY, my collaborators and I found the first unambiguous evidence of what’s known as “magnetization tunneling.” We were studying a collection of single-molecule magnets in which each molecule behaves like a tiny individual magnet. Let’s take a typical bar magnet, with the top being the north pole and the bottom the south pole. If you make that magnet smaller and smaller, the direction of the poles will fluctuate, primarily due to thermal fluctuations. (The magnet itself isn’t actually rotating—just the direction of its magnetization.) The magnet likes to point up or down; it doesn’t like to point left or right. To go from up to down, you have to go over an energy barrier. If you think in classical mechanical terms, once you get near absolute zero temperature, it should stop fluctuating because there isn’t enough thermal energy to get over the barrier, and the north pole will always be up or always be down. But quantum mechanics says that you can still go from up to down by “tunneling.” If you go to very low temperatures, and it can’t get over the barrier, the only way it can get from one side to the other is to pull out a little shovel and “tunnel” through the barrier. It goes from up to down without going anywhere in between.

There had been plenty of mostly circumstantial evidence of magnetization tunneling for many years, but the work we did was pretty much incontrovertible: we found a way of turning the tunneling on and off, and the places where it turned on were exactly what you’d expect from a simple theoretical model. That made a big splash. I shared the Agilent Technologies Europhysics Prize in 2002, awarded by the European Physical Society, and my thesis adviser won the Oliver Buckley Prize from the American Physical Society a few years after that. Our original paper is approaching 900 citations at this point.

In the Nature piece, they named two articles—one by myself and one by a group in France. That gave the impression that both articles were of equal priority. In fact, the other group’s paper was published several months later and their first paragraph states that they were corroborating our results. We just submitted a letter to Nature Physics, telling them that they didn’t assign priority correctly.

On truth-seeking

Sometimes journalism can be very straightforward. You go to a town meeting, record what people say and publish it. That’s “true,” but there can be deeper issues if you dig. The same is true in science. You can measure a sample with a standard technique, get results and write a paper. But science at its best is about seeking the answers to big questions.

I like to dig deep into a question and really try to find out how and why something happens. I was almost a philosophy major, and it’s always been important for me to understand the meaning of something, rather than just how it technically works. When I made this tunneling discovery, I saw that there was something interesting happening at a certain magnetic field. I slowed down the data taking there, just to get more data points, and I started thinking, “Is that fair? Am I giving too much weight to this little section?” (When I was a journalist, I was thinking, “Am I spending too much time talking about what this person said, instead of what that person said? Am I giving everybody equal weight?”) I decided, “Maybe I should just take data at the same rate over the whole range.” That started me down an interesting path of inquiry that eventually led to the discovery of tunneling.

On “the good life”

The good life is a romantic notion. You think, “If I achieve this thing, I can be happy and relaxed ad infinitum,” and as soon as you get there, you realize, “Well, you know, there are some downsides to this as well.” You have a nice house; you have to clean it. You have a beautiful daughter; you have to change her diapers. John Lennon famously said, “Life is what happens to you while you’re busy making other plans.” For me, the only thing that distinguishes the good life from ordinary life is that if it’s a good life, you’re not thinking about whether it’s a good life or not. You’re too busy living it.

Duke, a writer and editor at Amherst, wrote the cover story on Keith Millner ’92 for the Summer 2008 Amherst magazine.